&nbsp068 &nbspFXUS02 KWBC 180652 &nbspPMDEPD &nbsp &nbspEXTENDED FORECAST DISCUSSION &nbspNWS WEATHER PREDICTION CENTER COLLEGE PARK MD &nbsp152 AM EST SAT NOV 18 2017 &nbsp &nbspVALID 12Z TUE NOV 21 2017 - 12Z SAT NOV 25 2017 &nbsp&nbsp &nbsp..GUIDANCE/UNCERTAINTY PREFERENCES... &nbsp &nbspA DYNAMIC LEAD MID-UPPER LEVEL TROUGH/HEIGHT FALLS PROGRESS FROM &nbspTHE UPPER MIDWEST THROUGH THE GREAT LAKES/NERN US TUE-WED WITHIN &nbspNRN STREAM FLOW. THIS SUPPORTS A DEEPENED CLIPPER LOW TRACK AND &nbspSWATH OF PCPN ALONG THE US/CANADIAN BORDER ALONG WITH A &nbspREINFORCING COOLING SURGE AND A PERIOD OF LAKE EFFECT SNOWS IN THE &nbspWAKE OF SYSTEM PASSAGE. SEVERAL LESS CERTAIN WEAKER PROGRESSIVE &nbspSYSTEMS ARE SLATED TO FOLLOW LATER NEXT WEEK WITHIN THIS NRN &nbspSTREAM FLOW. &nbsp &nbspTHE EXTENT OF DIGGING OF EMBEDDED SRN STREAM IMPULSES UNDERNEATH &nbspTO THE LEE OF A BUILDING WARMING WRN US MID-UPPER LEVEL RIDGE &nbspEARLY NEXT WEEK AND MID-LATER NEXT WEEK POTENTIAL SRN STREAM &nbspTROUGH/LOW SEPARATION OVER THE GULF COAST REMAINS FURTHER &nbspCOMPLICATED BY POTENTIAL FOR NRN STREAM INTERACTION IN SOME &nbspSOLUTIONS. FORECAST SPREAD AND UNCERTAINTY REMAINS ABOVE NORMAL &nbspALONG WITH MODEL RUN TO RUN VARIANCE. OF THE ENSEMBLES...PREFER &nbspTHE ECENS THAT SHOWS MORE FLOW SEPARATION AND WEATHER FOCUS THAN &nbspTHE GEFS/CANADIAN/NAEFS. THIS MATCHES WPC CONTINUITY AND FITS THE &nbspOVERALL FLOW AMPLIFICATION UPSTREAM AS PER RECENT MODEL TRENDS. &nbsp &nbspMEANWHILE...CONTINUED INLAND FLOW OF PACIFIC IMPULSES FROM AN &nbspAMPLIFIED OFFSHORE MID-UPPER LEVEL MEAN TROUGH PROLONGS A WET &nbspPATTERN THAT INCLUDES ELEVATION SNOWS OVER THE NWRN US THROUGH THE &nbspEXTENDED THANKSGIVING BREAK...ALBEIT WITH QUICKLY GROWING TIMING &nbspUNCERTAINTY. &nbsp &nbspOVERALL...THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED &nbspFROM A BLEND OF THE 12 UTC GFS/ECMWF AND GEFS/ECMWF ENSEMBLES INTO &nbspTHANKSGIVING BEFORE TRANSITIONING TO AN ECMWF ENSEMBLE MEAN &nbspCENTERED SOLUTION BY DAYS 6/7 (NEXT FRI-SAT) THAT MAINTAINS MAX &nbspWPC CONTINUIY. &nbsp &nbsp&nbsp &nbsp..WEATHER HIGHLIGHTS &nbsp &nbspWET FLOW CONTINUES FOR THE PACIFIC NW WITH OCCASIONALLY HEAVY &nbspDAILY RAINS AND LOCALLY HEAVY ELEVATION SNOWS. UPPER RIDGING WILL &nbspSUPPORT ABOVE AVERAGE TEMPERATURES FROM THE SOUTHWEST THROUGH THE &nbspSOUTHERN GREAT BASIN/ROCKIES AND PLAINS...BUT COOLER THAN AVERAGE &nbspIN THE EASTERN US BEHIND A COLD FRONT. THERE IS A GOOD CHANCE FOR &nbspAPPRECIABLE PRECIPITATION ALONG THE GULF COAST AS LOW PRESSURE &nbspMEANDERS ALONG A SLOW MOVING FRONT. EXPECT SOME RAIN/SNOW AROUND &nbspTHE GREAT LAKES BUT GENERALLY NO PRECIPITATION FROM THE SOUTHWEST &nbspTO THE PLAINS AND MS VALLEY. &nbsp &nbsp&nbsp &nbsp..THANKSGIVING FORECAST &nbsp &nbspGENERALLY QUIET FOR MOST OF THE LOWER 48. PRECIPITATION WILL BE &nbspMOST CONCENTRATED IN THE PACIFIC NORTHWEST INTO NORTHERN &nbspCALIFORNIA AS WELL AS NORTHERN IDAHO/WESTERN MONTANA/NW WYOMING. &nbspORGANIZED RAIN IS ALSO QUITE POSSIBLE ALONG THE GULF COAST FROM &nbspTEXAS EASTWARD TO FLORIDA . RECORD HIGH TEMPS ARE POSSIBLE IN THE &nbspSOUTHWEST WITH WIDESPREAD 80S AND SOME 90S. &nbsp &nbspSCHICHTEL &nbsp &nbsp &nbsp